The invention is based on a feed pump for an internal combustion engine. A feed pump of this kind has been disclosed by DE 44 41 505; U.S. Pat. No. 5,597,291, and is used there for feeding fuel from a storage tank to a fuel injection pump of an internal combustion engine.
The feed pump is embodied as a geared feed pump which has a pair of gears that engage in an externally meshed fashion. The rotationally driven pair of gears feeds fuel from an intake chamber connected to the storage tank, along a supply conduit constituted between the end faces of the gears and the circumferential wall of the pump chamber, and into a pressure chamber from which a supply line leads to the fuel injection pump.
To control the pressure in the pressure chamber or the feed quantity of the feed pump, a bypass conduit is provided between the pressure chamber and the intake chamber in the pump housing of the feed pump, and a pressure valve that opens in the direction of the intake chamber is inserted into this bypass conduit. The opening of the bypass conduit is carried out via the pressure valve, which unblocks a particular opening cross section in the bypass conduit at a particular pressure differential between the pressure chamber and the intake chamber, as a function of the spring force of the valve spring. The opening time and opening stroke can be adjusted via the initial stress of the valve spring of the pressure valve, which is why it is possible to adjust the axial position of a clamping sleeve that acts as a counter-support.
Due to the fixed disposition of the bypass conduit in the pump housing, the known feed pump has the disadvantage that the individual feed pumps can only be used as clockwise or counter-clockwise feed pumps so that different feed pump types are required for different drive rotation directions, which increases manufacturing costs and limits a flexible utility of the feed pumps.